The present invention is directed to the field of hydraulic power cylinder actuators. As shown in FIG. 1, conventional hydraulic cylinders actuators in use today utilize a single piston 14 inside of a cylinder 12. High-pressure fluid is fed into the cylinder on one side of the piston 14, propelling the piston through the cylinder in the opposite direction. FIG. 1 shows a conventional cylinder hydraulic piston arrangement, using valves to allow the system to operate in both directions. The figure shows the piston in a position of mid-extension. The pump 16 is filling the left chamber while the fluid in the right chamber is being forced into the tank or reservoir of the system. At the point in which the piston is fully extended, the valve 18 is switched to the opposite position and the process may be reversed.
The conventional cylinder design is prone to high pressure leaks from the rod-end of the cylinder, causing an oil spill that can shut down the machinery operated by the cylinder. In many applications, extremely high hydraulic pressures must be produced to obtain the required forces. Such high working pressures can increase the factor of equipment failure. In conventional hydraulic actuator design, the cylinder wall is stronger than the piston operating rod. In high-load situations, this rod can bend, causing failure of the cylinder. This, combined with the possibility of high pressure oil leaks, could result in damage to machine and a danger to those who operate the machinery. Also, in conventional cylinder designs, the system power consumption is relatively high for the amount of power delivered. Still another problem with conventional cylinder designs is that they are very heavy, primarily because of the thickness of the materials used to make cylinders capable of handling the extremely high operating pressures required to obtain the desired results.